Personally I feel datasets completely fall down in complicated scenarios
.. I used to be a fan but experience has taught me otherwise. I still
use them for quick and dirties though .
For you scenario why even query ? Surely some simple code can filter the
data to what you need .
Ie foreach (Name name in Addresses)
If (name .StartsWith(praram)
....
or
Foreach DataRow row in Table.Rows
...
This works better with classes than Datasets, though typed datasets are
not that bad . Considering your limited amount of records you can store
all your data in memory and persist to a file ( I prefer binary) . I
would not bother with MSDE and Jet
Regards,
Ben
> -----Original Message-----
> From: Unmoderated discussion of advanced .NET topics.
[mailto:ADVANCED-
> [EMAIL PROTECTED] On Behalf Of Jon Rothlander
> Sent: Thursday, 7 July 2005 3:41 AM
> To: [email protected]
> Subject: Re: [ADVANCED-DOTNET] ADO.Net
>
> I think my originally posting may have been a little confusing. I
realize
> that there is not SQL engine in ADO.Net, but there is
> Dataset.Tables().Select(), which I guess is just another way to
filter. I
> simply wanted to point out what kind of work I need to do on the
client
> side. I need to recreate the SELECT statements aginst the dataset or
XML.
> I need the end result of both the client and server apps to be the
same.
>
> Your idea of stashing the data in local .mdb files may work for me as
99%
> of
> what I am doing is read-only. Are there any issues with Access MDB
files
> in
> .Net? Access is pretty well known for get corrupted. The small amout
of
> updating that would have to be stored locally can be handle via XML.
>
> >>And since your disconnected users will only ever be able to get a
subset
> of the
> >>data they got from their last connected query, do you really want to
> >>encourage the impression that they can run queries when offline?
> >>That sounds like an invitation to confusion to me...
>
> The data that they have access to is VERY small. Most of the 12 or so
> tables will only have a few dozen records. So I am planning that the
> users
> will be able to run queries locally while they are disconnectd. The
main
> point of the app is data entry and the queries are only used to
populate
> controls. Some of the queries get a little complex, which is what I'm
> having a problem with. I have NEVER needed to do anything complex
like
> this
> with a dataset. I have always been able to handle it in the SELECT
> statement and just do some simple filtering on the dataset. Now I
need to
> do a little more complex work on the client side, which is why I
running
> into areas that I have little experience with.
>
>
>
>
> -----Original Message-----
> From: Unmoderated discussion of advanced .NET topics.
> [mailto:[EMAIL PROTECTED] On Behalf Of Pardee, Roy
> Sent: Wednesday, July 06, 2005 11:31 AM
> To: [email protected]
> Subject: Re: [ADVANCED-DOTNET] ADO.Net
>
> There is no client-side SQL engine in ado.net. I think the thing that
> comes
> closest is the jet engine (the thing that gets exercised when you move
> data
> in & out of an .mdb file). Jet has a pretty nice implementation of
SQL,
> tho
> there are some annoying limitations (subqueries come to mind).
>
> I'd advise stashing your offline data in an .mdb and just swapping out
> DataAdapters as users connect & disconnect, except that I think that
would
> mess up ado.net's updating logic--you'll have to manage RowStates your
own
> self when time comes to push offline changes back to the db. I don't
know
> if that's more trouble than its worth.
>
> And since your disconnected users will only ever be able to get a
subset
> of
> the data they got from their last connected query, do you really want
to
> encourage the impression that they can run queries when offline?
> That sounds like an invitation to confusion to me...
>
> HTH,
>
> -Roy
>
> -----Original Message-----
> From: Unmoderated discussion of advanced .NET topics.
> [mailto:[EMAIL PROTECTED] On Behalf Of Jon
Rothlander
> Sent: Wednesday, July 06, 2005 8:52 AM
> To: [email protected]
> Subject: [ADVANCED-DOTNET] ADO.Net
>
>
> I've doing what I would think would be a very common use of ADO.Net,
but I
> cannot find much info on this in any of my book or online. What I'm
doing
> seems pretty simple.
>
> I have an app that can run in both a disconnted and connected state.
> When it is disconnected, it is disconnected from the SQL DB. My
client
> machine does not have access to a local database, so I am using XML on
the
> client. I am loading the XML into datasets to be processed.
>
> The problem I'm running into is that I cannot easily perform the same
> SELECT
> statements against the datasets that I can perform against SQL Server.
> For
> example, lets say that I have the following SQL SELECT statement...
>
> SELECT * FROM table1
>
> If I bring a copy of table1 from SQL server to the client machine and
save
> it as XML, I can reload the dataset using the local copy of XML.
> Reload the XML will recreate the same dataset as the SQL SELECT
statement
> created with I was connected to the Server.
>
> However, take the following SQL statement..
>
> SELECT ID, rtrim(ltrim(FirstName + ' ' + LastName, FROM table1 WHERE
> userid
> = '1' OR userid = NULL
>
> What options do I have in loading table1 into a dataset and them
> recreating
> this same SQL statement? What if the SQL statement was even more
complex
> with 3 or 4 tables, a few JOINS, etc? Do I have to build the dataset
> tables
> individually, then set up relationships, and them perform simple SQL
> statements one at a time while creating new datasets with each result?
>
> That seems to be the way the books show you. However, that seems to
be a
> major pain. I might as well right XML parsing code to handle it.
> Maybe creating a new dataset from SQL when the user is last connected,
but
> create one with the JOINS already in place. Then just use multiple
> table().Select
> () statements to drill into the records I need.
>
> What do you think is the best way to handle this sort of logic?
>
> Any ideas would be very much appreicated. I want to make sure I
approach
> this one correctly so I do not need to rewrite it down the road. I
also
> want to understand what options I have to make sure I am not missing
> something that would make this pretty easy to code.
>
> Best regards,
> Jon
>
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